Over the past three decades, consumption and supermarket sales of “ultra-processed” foods have continued to rise, potentially increasing individuals’ risks for developing certain kinds of cancers, according to a recent study published in BMJ.

“Diets in many countries have shifted towards a dramatic increase in consumption of ultra-procssed foods, since these foods are affordable, easy to prepare and almost ready to consume,” study authors Bernard Srour, PharmD, MPH, and Mathilde Touvier, Ph.D., both from Équipe de Recherche en Epidémiologie Nutritionnell in Paris, said in an interview with CURE.

Ultra-processed foods include items such as packaged bread products, sweet and savory packaged snacks, industrialized desserts, highly processed and/or preserved meat products, instant noodles and soups and other shelf-stable items, which usually have a high sugar, oil and/or fat content.

“Several surveys in Europe, the US, Canada, New Zealand and Brazil have suggested that ultra-processed food products contribute to between 25 and 50 percent of total daily energy intake,” Srour added.

The researchers observed 104,980 people (21.7 percent men and 78.3 percent women) who had no cancer history at baseline. They then followed these individuals and tracked their food intake and health events via online surveys to determine if ultra-processed food consumption increases the risk for cancer.

During a median follow-up time of five years, there were 2,228 cancers diagnosed, with the most common being breast (739 cases), prostate (281 cases) and colorectal (153 cases).

Results revealed that a 10 percent increase in the proportion of processed foods in an individual’s diet was associated with a 12 percent increase in their risk for developing cancer – in particular, an 11 percent risk for breast cancer specifically.

The researchers attributed this potential correlation to the quality of these foods, as well as their packaging. “The nutritional quality of ultra-processed foods (as they are rich in salt, saturated fatty acids and poor in fiber) is not the only mechanism explaining these associations. Some food additives, contaminants or plastic packages have carcinogenic effects, which might explain these associations,” Srour and Touvier said.

However, they noted that a causal link still cannot be established, and that additional baseline characteristics could have been contributing factors to this increased risk for cancer. For example, participants who had the highest intake of ultra-processed foods typically had some other known risk factors, such as being current smokers and having lower physical activity levels.

Not to mention, while a correlation was apparent in this study, the authors said that to establish a causal relationship between ultra-processed and cancer, a larger study must be done to confirm their findings, as well as a mechanistic study in vitro or in animals.

The researchers are already taking steps toward the next line of investigation in this field. They are currently launching a large-scale program on chronic exposure to food additives and health.

While people should not be overly alarmed at the cancer risk from processed foods until larger study results are published, the authors do recommend eating a minimally processed diet in the meantime.

“Caution is needed when extrapolating these findings to cancer patients in a context of tertiary prevention. However, in the absence of recommendations regarding ultra-processed foods consumption in cancer patients, we recommend cancer patients to privilege minimally processed foods,” Srour and Touvier said.